1. Field of the Invention
The present invention relates to a photosensitive thick film composition, and more particularly to a photosensitive thick film composition suitable for use in producing electrodes with high resolution and high contrast.
2. Background of the Invention
In optotronic industry, the popular processes for producing electrode material used for large flat panel displays can be classified into thin film process and thick film process. The thin film process mainly uses sputtering, chemical vapor deposition (CVD), or physical vapor deposition (PVD) to form multi-layered electrode, such as Cr/Cu/Cr, Al/Cr, Cr/Ni, or Cr/Ag. The thick film process mainly uses photolithography or screen printing. However, in the thin film process, since Cu is oxidized easily in the deposition process, it is required to form a Cr/Cu/Cr three-layered electrode. Moreover, since the expansion coefficients of Cr and Cu are different, during high temperature sintering, cracks are easily generated at the interface. Moreover, light reflects on Cr, so the contrast decreases. The thin film process has the above-mentioned drawbacks and the integral facilities and process are complicated, thus increasing the production cost. Therefore, the present trend is to use the simpler thick film process.
In the thick film process, the resolution using screen printing has achieved to 60-70 xcexcm in the present time. Nevertheless, the improvement in resolution using screen printing is limited in the future. The process of using photolithography technique to form the photosensitive thick film of electrodes is very simple and results in high resolution. Also, Cu oxidation will not occur. Therefore, the thick film process by photolithography technique has extensively drawn the industry""s attention. There is still a need to develop a photosensitive thick film material with superior properties.
The first object of the present invention is to provide a photosensitive thick film composition that can produce electrode material with high resolution and high contrast.
To achieve the object, the photosensitive thick film composition includes the following components:
(A) an acrylic copolymer having the repeating unit represented by formula (I) 
wherein
R1 and R2 are independently hydrogen, C1-20 linear or branched alkyl, C3-20 cyclic or polycyclic alkyl, C1-6 linear, branched, or cyclic alkoxy, silyl, or C1-6 alkylsilane, and only one of R1 and R2 is hydrogen,
the molar ratio of Y to Z is 0.15-0.7:0.15-0.7;
(B) a photoinitiator;
(C) a reactive monomer;
(D) a conductive metal;
(E) glass powder;
(F) an additive; and
(G) an organic solvent;
wherein components (B), (C), (D), (E), (F), and (G) are present in weight ratios of 10-50:40-90:400-800:20-90:0.1-0.8:90-180 based on 100 weight parts of component (A).
The second object of the present invention is to provide another photosensitive thick film composition that can produce electrode material with high resolution and high contrast.
To achieve the object, the photosensitive thick film composition includes the following components:
(A) an acrylic copolymer having the repeating unit represented by formula (II) 
wherein
R1 and R2 are independently hydrogen, C1-20 linear or branched alkyl, C3-20 cyclic or polycyclic alkyl, C1-6 linear, branched, or cyclic alkoxy, silyl, or C1-6 alkylsilane, and only one of R1 and R2 is hydrogen,
the molar ratio of X, Y to Z is 0.01-0.5:0.15-0.7:0.15-0.7;
(B) a photoinitiator;
(C) a reactive monomer;
(D) a conductive metal;
(E) glass powder;
(F) an additive; and
(G) an organic solvent;
wherein components (B), (C), (D), (E), (F), and (G) are present in weight ratios of 10-50:40-90:400-800:20-90:0.1-0.8:90-180 based on 100 weight parts of component (A).